DNA Narcolepsy Test

Do you struggle to stay awake throughout the day?
And an afternoon nap (or two!) is essential for you to function?

You may be affected by a sleeping disorder known as narcolepsy.

What is narcolepsy?

It is a neurological disorder characterized by extreme daytime sleepiness and uncontrollable episodes of falling asleep during the day. This excessive daytime sleepiness should not be mistaken for the afternoon slump, since neurological defects are responsible for narcolepsy, rather than just sleep deprivation or lack of caffeine!

Who is at risk of narcolepsy?

Family members of an affected individual have a 20X – 40X increased risk of developing narcolepsy, indicating a strong genetic basis for the disorder. The genetic variant most closely associated with this sleeping disorder is HLA-DQB1*06:02. Individuals with this variant have a 7X to 25X increased risk, although one recent European study indicates a much higher odds ratio of approximately 250-fold! Multiple other HLA-DQB1 variants also exist, and many of these provide some protection, complicating the risk analyses.

What are the symptoms of narcolepsy?

This disorder is often incorrectly diagnosed because it involves a wide variety of neurological symptoms. The symptoms include:

How common is narcolepsy?

Between 1 in 2000 and 1 in 5000 people are thought to be affected by narcolepsy. However, only about 25% are correctly diagnosed, and often people are instead mistakenly diagnosed with psychiatric or emotional problems. Family members of an affected individual also have a 20X – 40X increased risk, indicating a strong genetic basis for the disorder.

The autoimmunity theory

About 70% of people with narcolepsy also suffer from cataplexy, which is caused by lower levels of a neurotransmitter named hypocretin (also called orexin). However, no genetic changes have been observed in the hypocretin gene. The neurons that produce hypocretin gradually die off in individuals with narcolepsy. Given the role of HLA-DQ proteins in immunity, it is believed that they play a role in this cell death; supporting the hypothesis that narcolepsy is an autoimmune disease. Celiac disease is another autoimmune disease that occurs due to changes in the HLA-DQ genes. The HLA-DQ changes in celiac disease cause an aberrant immune response and severe intestinal lining damage, triggered by the consumption of gluten. The trigger (if any) for narcolepsy is currently unknown, but a similar aberrant autoimmune response occurs, this time resulting in the destruction of healthy (and essential) hypocretin-producing neurons.

Genetics of narcolepsy

90-99% of individuals with narcolepsy carry a variant of the HLA-DQB1 gene known as the HLA-DQB1*06:02 allele. Approximately 15 – 25% of the unaffected worldwide population, also have HLA-DQB1*06:02, so other factors must also contribute to this disorder.